I don't know if this helps for PCBs but Kapton is a UL recognized
material.  It is in the 1996 Plastics Recognized Components Directory on
page 128.
 ----------
From: KoizumiT
To: [log in to unmask]
Subject: Why Polyimide is Not ANSI?
Date: Wednesday, November 20, 1996 2:25AM

     Dear TechNetters:

       I am wondering why Polyimide Film materials such as Kapton,
Apical,
     Upilex etc. are not recognized as a same ANSI grade although these
PI
     films have very similar molecular formula and properties.

       As we are manufacturing Flexible Printed Circuits using these
     materials, our UL application is very complexed because they are
not
     recognized as ANSI.

       Does anyone trying to set up ANSI grade for polyimide films in
use
     of FPC?  Or does anyone knows suitable forums for this discussion?

     Best Regards,

     Toru Koizumi(Mr)
     Fujikura Ltd. Japan
     [log in to unmask]

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